Timepiece driving apparatus and time calculating apparatus

ABSTRACT

A timing device having a generator unit, a storage unit, and a drive unit is provided. The generator unit has a generating coil and converts kinetic energy into electric energy by utilizing electromagnetic induction. The storage unit stores the electric energy. The drive unit has a piezoelectric actuator, a mechanical structure, and a time display unit. The piezoelectric actuator is supplied with the electric energy from the storage unit and is caused to oscillate according to signals from the communication unit. The mechanical structure is provided with a time display unit and is driven by the piezoelectric actuator.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a timing device, andparticularly relates to a timepiece and a radio-controlled timepieceequipped with a generating device that utilizes electromagneticinduction.

[0003] 2. Background Information

[0004] Timepieces with electromagnetic generators that are equipped witha power generator having a generating coil, and that generateelectricity with electromagnetic induction and store the generatedelectrical power to be used as a driving power source, are currentlybeing commercialized (for example, see Japanese Patent No. 2000-147167).

[0005] The conventional timepieces with electromagnetic generatorsdescribed above have a large leakage field when the electric motorgenerates electricity, the leakage field has no small effect on theelectromagnetic motor for the timepiece, and it is possible that thetimepiece may stop due to the leakage field and the displayed time willbe slowed.

[0006] Also known in conventional practice are radio-controlledtimepieces wherein an LF standard wave (JG2AS) is received from theoutside at a specific cycle and the displayed time of theelectromagnetic correction timepiece is corrected based on time datasuperposed on this LF standard wave (JG2AS).

[0007] The time data included in the LF standard wave used to correctthe displayed (time of a radio-controlled timepiece have 60 seconds inone cycle (=one piece of data). This time data include the total numberof days from the first day of the first month of the current year, thecurrent hour, the current minutes, and other such data.

[0008] However, in conventional radio-controlled timepieces, whenelectromagnetic noise is generated by a stepping motor for driving thetime-displaying pointers when an LF standard wave is received by areceiving antenna, the time data included in the LF standard wave can nolonger be correctly received, and reception may be impossible orincorrect.

[0009] To resolve these problems, the technique in Japanese Patent No.3163403 employs a configuration in which a circuit is provided forstopping the stepping motor while the LF standard wave is received, thegeneration of electromagnetic noise originating in the driving of thestepping motor is prevented, and the current time is corrected after theLF standard wave is received.

[0010] Therefore, the radio-controlled timepiece described in JapanesePatent No. 3163403 has had drawbacks in that the circuit configurationis complicated and the time cannot be correctly displayed while the LFstandard wave is received.

[0011] It will be clear to those skilled in the art from the disclosureof the present invention that an improved timepiece is necessary becauseof the above-mentioned considerations. The present invention meets therequirements of these conventional technologies as well as otherrequirements, which will be apparent to those skilled in the art fromthe disclosure hereinbelow.

SUMMARY OF THE INVENTION

[0012] A drive device relating to the present invention includes agenerator unit, a storage unit, and a drive unit. The generator unit hasa generating coil, and converts kinetic energy into electric energy byutilizing electromagnetic induction. The storage unit stores theelectric energy. The drive unit has a piezoelectric actuator and amechanical structure. The piezoelectric actuator is supplied with theelectric energy from the storage unit. The mechanical structure isdriven by means of the piezoelectric actuator.

[0013] The timing device relating to the present invention includes anantenna, a communication unit, and a drive unit. The communication unitcommunicates with an external communication device via the antenna. Thedrive unit has a piezoelectric actuator and a mechanical structure. Themechanical structure has a time display unit for displaying timeinformation. The piezoelectric actuator vibrates according to signalsfrom the communication unit. The mechanical structure is driven by meansof the piezoelectric actuator, and the time information is displayed onthe time display unit.

[0014] The objects, characteristics, merits, and other attributes of thepresent invention described above shall be clear to those skilled in theart from the description of the invention hereinbelow. The descriptionof the invention and the accompanying diagrams disclose the preferredembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Referring to the accompanying diagrams, which partially disclosethe present invention:

[0016]FIG. 1 is a structural block diagram of the timing device relatingto the first embodiment;

[0017]FIG. 2 is a partial plan view of the timing device relating to thefirst embodiment;

[0018]FIG. 3 is a cross-sectional view of part of the timing devicerelating to the first embodiment;

[0019]FIG. 4 is an explanatory diagram of the structure of apiezoelectric actuator;

[0020]FIG. 5 is a side view of a piezoelectric actuator;

[0021]FIG. 6 is a plan view of a piezoelectric actuator;

[0022]FIG. 7 is an enlarged view of the contact section of apiezoelectric actuator;

[0023]FIG. 8 is a cross-sectional view of part of the timing devicerelating to the second embodiment;

[0024]FIG. 9 is a cross-sectional view of part of the timing devicerelating to the third embodiment;

[0025]FIG. 10 is a diagram illustrating the frequency-impedancecharacteristics of the specific configuration of a piezoelectricactuator;

[0026]FIG. 11 is an explanatory diagram of an example of the electrodearrangement of a piezoelectric actuator;

[0027]FIG. 12 is an explanatory diagram of the electrode arrangement foranother piezoelectric actuator;

[0028]FIG. 13 is an explanatory diagram of the arrangement of electrodesin a piezoelectric actuator driven both forwards and backwards;

[0029]FIG. 14 is an explanatory diagram of another arrangement ofelectrodes in a piezoelectric actuator driven both forwards andbackwards;

[0030]FIG. 15 is a partial plan view of the timing device relating tothe fourth embodiment;

[0031]FIG. 16 is a cross-sectional view of one part of the timing devicerelating to the fourth embodiment;

[0032]FIG. 17 is a cross-sectional view of another part of the timingdevice relating to the fourth embodiment; and

[0033]FIG. 18 is a cross-sectional view of part of the timing devicerelating to the fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Embodiments of the present invention will now be described withreference to the drawings. As will be apparent from the disclosure ofthe present invention to those skilled in the art, the description ofthe invention embodiments is intended solely to illustrate the presentinvention and should not be construed as limiting the scope of thepresent invention, which is defined by the claims described below or bytheir equivalents.

[0035] The preferred embodiments of the present invention will now bedescribed with reference to the drawings.

[0036] [1] First Embodiment

[0037] The first embodiment will first be described.

[0038]FIG. 1 is a structural block diagram showing an analog electronictimepiece according to the present embodiment. FIG. 2 is a plan viewshowing the same analog electronic timepiece.

[0039] In the timing device of the first embodiment, the object ofcontrol for the drive device is a time display mechanism 5, and the timedisplay mechanism 5 is operated by means of a piezoelectric actuator 41constituting the drive device.

[0040] An electric power source 1 has a generating coil and anoscillating weight to be hereinafter described, and includes a generatorunit (generating means) 1A for generating electricity by converting thekinetic energy of the oscillating weight to electric energy byelectromagnetic induction, a rectifying circuit 1B for rectifying the ACpower generated by the generator unit 1A into DC power, and a secondarybattery (storage means) 1C for storing the rectified DC power.

[0041] In FIG. 1, the electric energy from the electric power source 1is received and an oscillating circuit 201 of an electronic circuit 2oscillates at a standard signal, which is 32,768 Hz. The standard signalof 32,768 Hz is converted to 1 Hz in a divider circuit 202. A signalfrom the divider circuit 202 is sent to a control circuit 225. Thiscontrol circuit 225 controls the supply timing for the drive pulse ofthe piezoelectric actuator 41, which is the drive source for the timedisplay mechanism 5. The control circuit 225 then inputs a drive pulsecommand signal to an oscillating circuit 2361, which sends the drivepulse to the piezoelectric actuator 41.

[0042] The drive pulse command signal with controlled supply timing isinputted from the control circuit 225 to the oscillating circuit 2361,and is then inputted to an electric motor drive circuit 2363 via awaveform shaping circuit 2362. This electric motor drive circuit 2363supplies a drive pulse to the piezoelectric actuator 41. Thepiezoelectric actuator 41 converts the electric energy into mechanicalenergy according to the drive pulse, and utilizes the piezoelectriceffect to push the external periphery of the driven body (rotor) 51. Therotor 51, rotated by the pushing action of the piezoelectric actuator41, rotatably drives a transmission mechanism (reduction gear train) 4and the time display mechanism 5. The display on the time displaymechanism 5 is corrected by means of a time correction device 8.

[0043]FIG. 2 is a partial plan view of the timing device relating to thefirst embodiment. FIG. 3 is a cross-sectional view of part of the timingdevice.

[0044] The timing device 10 is a wristwatch designed for use by wrappinga belt coupled with the main body of the device around the wrist of theuser.

[0045] In general terms, the timing device 10 includes an electric powersource 1 (see FIG. 1), and also has a timing unit (drive means) andoperating unit 14 to be hereinafter described.

[0046] The electric power source 1 of the timing device 10 includes anoscillating weight 21, an oscillating weight wheel 22, a generatingrotor intermediate wheel 23, a generating rotor 24, a generating stator25, a generating coil 26, a secondary battery 1C, a secondary batterypositive terminal 27 and secondary battery negative terminal 28 forelectrically connecting the secondary battery 1C and a base plate, anoscillating weight support 29, and a bearing 30. The generating rotor24, generating stator 25, and generating coil 26 constitute thegenerator unit 1A.

[0047] In general terms, the timing unit includes a piezoelectricactuator 41 for driving a second hand as a pointer component, atransmission mechanism (gear train section) 4 for transmitting thedriving force for driving the pointer, a crystal oscillator 44 forkeeping time, and a timing IC 45 for performing various timing processeson the basis of standard oscillation signals for timing.

[0048] The transmission mechanism 4 is similar to a regular analogtimepiece and includes a rotor 51, a rotor pinion 52, a fifth wheel andpinion 53, a fourth wheel and pinion 54, a third wheel and pinion 55, asecond wheel and pinion 56, an hour wheel 57, a second hand 61, a minutehand 62, an hour hand (hour display means) 63, a minute wheel 64, arotor press member 65, and a train wheel bridge 66.

[0049] The operating unit 14 includes a setting stem 71, a setting lever72, and a yoke 73, and is designed to be able to perform varioussettings, including time setting and time correction, similar to othertiming devices. The setting stem 71, setting lever 72, and yoke 73 aremade from steel materials in order to be more compact.

[0050] Furthermore, the timing device 10 includes a main plate 75 and acircuit press plate 76 as structural components.

[0051] The relative arrangement of the electromagnetic generator and thepiezoelectric actuator will now be described with reference to FIGS. 2and 3.

[0052] In the first embodiment, assuming there is a plane perpendicularto the thickness direction of the timing device 10, the generator unit1A is disposed at a location in which the positive projection of thegenerator on this plane does not overlap the positive projection of thepiezoelectric actuator 41 on this plane.

[0053] Such an arrangement allows the thickness of the timing device 10to be reduced and makes it possible to configure a thin wristwatch withan electromagnetic generator.

[0054] The piezoelectric actuator constituting the drive device will nowbe described.

[0055]FIG. 4 is an explanatory diagram of the configuration of thepiezoelectric actuator.

[0056] The piezoelectric actuator 41 is configured with a stainlesssteel plate or another such reinforcing plate 115 held between twoplate-shaped piezoelectric elements 113 and 114, as shown in FIG. 4. Aholding section 41A (see FIG. 2), a contact section 41B, and a balancesection 41C are formed integrally on the reinforcing plate 115. Thislayered structure makes it possible to suppress the over-amplitude ofthe piezoelectric actuator 41 and the damage to the piezoelectricelements 113 and 114 by external forces.

[0057] Electrodes 113A and 114A are arranged on top of the piezoelectricelements 113 and 114 as shown in FIG. 4, and the voltage from a drivecircuit 200 is supplied to the piezoelectric elements 113 and 114 viathese electrodes 113A and 114A.

[0058] When the polarization direction of the piezoelectric element 113and the polarization direction of the piezoelectric element 114 areopposite, the piezoelectric elements 113 and 114 are displaced so as toexpand and contract if an alternating-current drive signal is suppliedfrom the drive circuit 200, such that the electric potentials at thetop, middle, and bottom in the diagram are +V, −V, and +V (or −V, +V,and −V), respectively.

[0059] The +V drive signal and the −V drive signal arealternating-current signals whose phases have been reversed. Therefore,the amplitude of the oscillation created in the piezoelectric element113 on top of the reinforcing plate 115 and the piezoelectric element114 on the bottom can be increased compared to when 0 V is applied tothe reinforcing plate 115 (when the reinforcing plate 115 is connectedto the grounding wire of the drive circuit 200). For the sake ofsimplicity, the power supply electrode in contact with the piezoelectricelements 113 and 114 is omitted and only the electrodes 113A and 114Apositioned on the outer side are shown in FIG. 4.

[0060] Lead titanate zirconate, quartz, lithium niobate, bariumtitanate, lead titanate, lead metaniobate, polyvinylidene fluoride, zinclead niobate, lead scandium niobate, or the like is used as thepiezoelectric elements 113 and 114.

[0061] The operation of the piezoelectric actuator 41 will now bedescribed.

[0062] When an alternating-current drive signal is applied to thepiezoelectric elements 113 and 114 from the drive circuit 200 via theelectrodes 113A and 114A, oscillation that expands and contracts in thelongitudinal direction is created in the piezoelectric elements 113 and114. In this case, the piezoelectric elements 113 and 114 createlongitudinal oscillation that expands and contracts in the longitudinaldirection, as shown by the arrow in FIG. 5. When the piezoelectricactuator 41 is electrically vibrated by the longitudinal oscillation dueto the application of a drive signal to the piezoelectric elements 113and 114, an angular momentum is created about the center of gravity ofthe piezoelectric actuator 41 by the unbalanced weight of thepiezoelectric actuator 41. This angular momentum induces curvedsecondary oscillation whereby the piezoelectric actuator 41 swings inthe width direction, as shown in FIG. 6. At this point a greater degreeof curved oscillation can be induced to create a greater angularmomentum by disposing the contact section 41B on the tip of thepiezoelectric actuator 41 opposite from the balance section 41C.

[0063] Thus, creating longitudinal oscillation and curved oscillation inthe piezoelectric actuator 41 and combining these two types ofoscillation causes the area at which the contact section 41B of thepiezoelectric actuator 41 and the rotor 51 come in contact to move alongan elliptic path. As a result of the movement of the contact section 41Balong an elliptic path in the direction of the timepiece, the force ofthe contact section 41B pushing on the rotor 51 increases when thecontact section 41B is in a position expanded toward the rotor 51, andthe force of the contact section 41B pushing on the rotor 51 decreaseswhen the contact section 41B is expanded to a position distanced fromthe rotor 51. Therefore, the rotor 51 is rotatably driven in thedirection of displacement of the contact section 41B while both types ofpressure are large, or, in other words, when the contact section 41B isin a position expanded toward the rotor 51.

[0064] As described above, the piezoelectric actuator 41 rotatablydrives the rotor 51 by elliptical movement due to both the longitudinaloscillation and the curved oscillation. At this point, the rotor 51 ispressed against the contact section of a second drive actuator by asecond rotor pressure member 65, whereby the rotor 51 is rotatablydriven in a reliable manner.

[0065] The rotational driving of the rotor 51 causes the rotor pinion 52to rotate and the fifth wheel and pinion 53 interlocking with the rotorpinion 52 to be rotatably driven.

[0066] Furthermore, the fifth wheel and pinion 53 interlocks with thefourth wheel and pinion 54, causing the second hand 61 fixed to thefourth wheel and pinion 54 to move.

[0067] The third wheel and pinion 55 interlocking with the fourth wheeland pinion 54 is also rotatably driven.

[0068] Furthermore, the third wheel and pinion 55 interlocks with thesecond wheel and pinion 56 and with the minute wheel 64 via the secondwheel and pinion 56, and movement is induced in the minute hand 62 fixedto the second wheel and pinion 56 and in the hour hand 63 fixed to thehour wheel 57.

[0069] The electric power source 1 includes an oscillating weight 21, anoscillating weight wheel 22, a generating rotor intermediate wheel 23, agenerating rotor 24, a generating stator 25, a generating coil 26, asecondary battery 1C, a secondary battery positive terminal 27 andsecondary battery negative terminal 28 for electrically connecting thesecondary battery 1C and the circuit board, an oscillating weightsupport 29, and a bearing 30. The generating rotor 24, generating stator25, and generating coil 26 constitute the generator unit 1A.

[0070] The operation of the electric power source 1 will now bedescribed.

[0071] When the oscillating weight 21 of the electric power source 1rotates due to the hand movement of the user with the timing device 10,rotation is induced in the oscillating weight wheel 22 supported by theoscillating weight support 29 via the bearing 30 in a manner that allowsintegral rotation with the oscillating weight 21.

[0072] The oscillating weight wheel 22 interlocks with the generatingrotor intermediate wheel 23, causing the generating rotor intermediatewheel 23 to rotate.

[0073] Furthermore, the generating rotor intermediate wheel 23interlocks with the generating rotor 24, and the rotation of thegenerating rotor 24 within the generating stator 25 creates AC power inthe generating coil 26 by electromagnetic induction.

[0074] At this point, the AC power generated by the generator unit 1A isrectified into DC power by the rectifying circuit 1B (see FIG. 1) and isstored in the secondary battery 1C. The CD power stored in the secondarybattery 1C is then supplied to all the circuits via the secondarybattery positive terminal 27 and the secondary battery negative terminal28. In the first embodiment the secondary battery 1C is preferablydisposed so as not to overlap with the piezoelectric actuator 41 or thegenerator unit 1A within an imaginary plane perpendicular to thethickness direction of the timing device 10.

[0075] Also, the operating unit 14 is preferably disposed so as not tooverlap with the timing IC 45 within the imaginary plane perpendicularto the thickness direction of the timing device 10. Furthermore, thesetting stem 71, setting lever 72, and yoke 73 constituting theoperating unit 14 are made from steel materials, and therefore arepreferably disposed at a position facing the generator unit 1A acrossthe transmission mechanism 4 so as not to create magnetism.

[0076] In the first embodiment, the electromagnetic noise resulting fromthe power generation of the electromagnetic generator has no effectbecause a piezoelectric actuator is used to drive the pointers.Therefore, the driving of the pointers does not stop and the displayedtime is not slowed. Even if the generating coil has a high magneticfield, the time display is not affected thereby, and the time isaccurately displayed. Also, power can be generated efficiently even ifthe magnetic field of the generating coil is set high, because theelectromagnetic step motor does not change the magnetic flow duringpower generation.

[0077] Also, the piezoelectric actuator and the generator unit(electromagnetic generator) can be disposed roughly in the same planeand the piezoelectric actuator for driving the pointers can be disposednear the generator unit, so the timing device, the driving device, andthe like can be reduced in size and thickness. Improved magneticresistance to prevent malfunctions in the electromagnetic step motormust be provided in order to be able to dispose the electromagnetic stepmotor nearby while improving the power generating properties of thegenerator unit 1A, and to accomplish this, it is necessary to increasethe number of turns in the coil of the electromagnetic step motor. As aresult, it is possible to improve the magnetic resistance of theelectronic timepiece and to obtain a drive that requires less energybecause of an increase in the coil resistance of the electromagneticstep motor. However, the outer shape of the coil of the electromagneticstep motor becomes wider, so the thickness thereof cannot be increasedto near the center of rotation of the oscillating weight, which resultsin hindering the improvement of the power generating properties.Accordingly, in the first embodiment, assuming there is a planeperpendicular to the thickness direction of the timing device 10, thegenerator unit 1A is disposed at a location in which the positiveprojection of the generator on this plane does not overlap the positiveprojection of the piezoelectric actuator 41 on this plane, and thereforeit is possible to improve the power generating properties because thethickness can be increased to the vicinity of the center of rotation ofthe oscillating weight, and the moment of inertia can be made greater.

[0078] [2] Second Embodiment

[0079] In the first embodiment described above, assuming there is aplane perpendicular to the thickness direction of the timing device 10(a surface perpendicular to the plane of paper), the generator unit 1Ais disposed at a location in which the positive projection of thegenerator unit 1A on this plane does not overlap the positive projectionof the piezoelectric actuator 41 on this plane.

[0080] In the second embodiment, the generator unit 1A is disposed at alocation in which at least part of the positive projection of thegenerator on the aforementioned plane overlaps the positive projectionof the piezoelectric actuator 41 in a plane perpendicular to thethickness direction of the timing device.

[0081]FIG. 8 is a cross-sectional view of part of the timing device ofthe second embodiment. In FIG. 8, the same sections are denoted by thesame symbols as in FIGS. 2 and 3. Also in FIG. 8, the symbol 80 denotesa small iron wheel and the symbol 81 denotes a clutch wheel, and thesemembers interlock with each other due to the operation of the settingstem 71, and are used to correct the time.

[0082] Assuming there is a plane perpendicular to the thicknessdirection, the generator unit 1A is disposed at a location in which atleast part of the positive projection of the generator unit 1A on thisplane overlaps the positive projection of the piezoelectric actuator 41on this plane.

[0083] Such a configuration makes it possible to reduce the size of thetiming device or other such drive device. Also, since the generator unit1A and the piezoelectric actuator 41 are disposed to be partiallyoverlapping, the capacity of the secondary battery 1C can beproportionately increased and the service life of the timing device orother such drive device can be extended. Furthermore, since thegenerator unit 1A and the piezoelectric actuator 41 can be disposed tobe partially overlapping, the wiring distance of the entire circuit canbe shortened and the drive device can be driven with reduced energybecause the secondary battery 1C, the electronic circuit 2, and othersuch electric elements can be positioned adjacent both to the generatorunit 1A and to the piezoelectric actuator 41. Additionally, since thegenerator unit 1A and the piezoelectric actuator 41 can be disposed tobe overlapping, another piezoelectric actuator can be disposed in theopen space and the drive device can have multiple functions.

[0084] Furthermore, electromagnetic noise resulting from the powergeneration of the electromagnetic generator has no effect because apiezoelectric actuator is used to drive the pointers, similar to thefirst embodiment. Therefore, the driving of the pointers does not stopand the displayed time is not slowed.

[0085] [3] Third Embodiment

[0086] In the third embodiment, either the generator unit 1A or thepiezoelectric actuator 41 is disposed on one side of the main plate,which is a structural member, while the other is disposed on the otherside of the main plate.

[0087]FIG. 9 shows a cross-sectional view of part of the timing deviceof the third embodiment. In FIG. 9, similar components are denoted bythe same symbols as in FIG. 8.

[0088]FIG. 9 shows an example in which the generator unit 1A is disposedon the rear side (top side in FIG. 9) of the main plate 75, and thepiezoelectric actuator 41 is disposed on the front side (bottom side inFIG. 9) of the main plate 75.

[0089] Assuming there is a plane perpendicular to the thicknessdirection of the timing device 10, such a configuration makes itpossible to dispose the generator unit 1A and the piezoelectric actuator41 at a location in which the positive projection of the generator unit1A on this plane overlaps the positive projection of the piezoelectricactuator 41 on this plane, and to reduce the size of the timing deviceor other such drive device. Also, since the generator unit 1A and thepiezoelectric actuator 41 can be disposed to be overlapping, thecapacity of the secondary battery 1C can be increased and the servicelife of the timing device or other such drive device can be extended.Furthermore, since the generator unit 1A and the piezoelectric actuator41 can be disposed to be overlapping, the wiring distance of the entirecircuit can be shortened and the drive device can be driven with reducedenergy because the secondary battery 1C, the electronic circuit 2, andother such electric elements can be positioned adjacent both to thegenerator unit 1A and to the piezoelectric actuator 41. Additionally,since the generator unit 1A and the piezoelectric actuator 41 can bedisposed to be overlapping, another piezoelectric actuator can bedisposed in the open space and the drive device can have multiplefunctions.

[0090] Furthermore, electromagnetic noise resulting from the powergeneration of the electromagnetic generator has no effect because apiezoelectric actuator is used to drive the pointers, similar to thesecond embodiment. Therefore, the driving of the pointers does not stopand the displayed time is not slowed.

[0091] [4] Modification of the First Through Third Embodiments

[0092] The specific configuration of the piezoelectric actuator 41 wasnot described above, but specifically, the following aspects arepossible.

[0093] First, a configuration based on the following shape is employedto improve the drive efficiency of the piezoelectric actuator 41.Specifically, the dimensions of the piezoelectric actuator 41 may be setas follows.

[0094] 7 mm×2 mm×0.4 mm

[0095] Two PZT's (trademark) with a thickness of 0.15 mm are used as thepiezoelectric elements, and a stainless steel plate with a thickness of0.1 mm is used as the base plate.

[0096] Employing such an aspect ratio of approximately 7 mm×2 mm allowsthe resonance frequencies of the longitudinal oscillation and the curvedsecondary oscillation described above to be substantially equal, andmakes efficient elliptical driving possible.

[0097] Also, the resonance frequency of the curved secondary oscillationin this case is preferably within a range of 0.97 to 1.03 times theresonance frequency of the longitudinal oscillation.

[0098] For example, the resonance frequency is specifically as follows.

[0099] Longitudinal oscillation: 284.3 kHz

[0100] Curved secondary oscillation:288.6 kHz (1.015 times the resonancefrequency of the longitudinal oscillation)

[0101] Satisfactory elliptical oscillation can be obtained in thepiezoelectric actuator 41 by setting the resonance frequency as in thisexample.

[0102] However, the resonance frequency of the longitudinal oscillationand the resonance frequency of the curved secondary oscillation can beeasily controlled by the aspect ratio of the piezoelectric actuator 41.In the example described above, the difference in resonance frequenciesis reduced when the width is less than 2 mm at a fixed length (7 mm).The difference in resonance frequencies also increases when the widthexceeds 2 mm.

[0103] Essentially, varying the width alone has no effect on theresonance frequency of the longitudinal oscillation, but causesvariations solely in the resonance frequency of the curved secondaryoscillation.

[0104] More specifically, it is clear that although the resonancefrequencies vary with the Young's modulus of the piezoelectric elementsor the reinforcing plate and must be optimized accordingly, the aspectratio is preferably about 7:2. The resonance frequency of the curvedsecondary oscillation decreases with the mass of the contact section 41Bof the piezoelectric actuator 41.

[0105] The setting of the optimal drive frequency will now be described.

[0106]FIG. 10 is a diagram showing the frequency-impedancecharacteristics of a specific configuration of the piezoelectricactuator.

[0107] The frequency-impedance characteristics of the piezoelectricactuator 41 have an antiresonant frequency f₀ between the minimum valueof the longitudinal oscillation (resonance frequency of the longitudinaloscillation) f₁ and the minimum value of the curved secondaryoscillation (resonance frequency of the curved secondary oscillation)f₂.

[0108] In the example described above, the longitudinal oscillationresonance frequency f₁ is 284.3 kHz, and the curved secondaryoscillation resonance frequency f₂ is 288.6 kHz. Therefore, it ispossible to induce simultaneously longitudinal and curved secondaryoscillations by setting the drive frequency (excitation frequency) ofthe piezoelectric actuator 41 at 280 kHz to 290 kHz.

[0109] In this case, a frequency between the longitudinal oscillationresonance frequency f₁ and the curved secondary oscillation resonancefrequency f₂ is preferably set as the drive frequency of thepiezoelectric actuator 41. In the example described above, the drivefrequency of the piezoelectric actuator should be set as follows.

[0110] f₁=284.3 kHz≦drive-frequency≦f₂=288.6 kHz

[0111] More preferably, the drive-frequency of the piezoelectricactuator should be greater than the antiresonant frequency f₀ locatedbetween the longitudinal oscillation resonance frequency f₁ and thecurved secondary oscillation resonance frequency f₂, and should be lessthan the curved secondary oscillation resonance frequency f₂.

[0112] Specifically, the following condition should be observed.

[0113] f₀<drive-frequency≦f₂

[0114] As a result, it is possible to obtain a greater ellipticaloscillation (combination of longitudinal and curved secondaryoscillations), and more efficient driving is also possible.

[0115]FIG. 11 is an explanatory diagram of an example of the electrodearrangement of a piezoelectric actuator.

[0116] The piezoelectric actuator 400A of the present modification isprovided solely with a full electrode 404, as shown in FIG. 11.

[0117] A mechanically unbalanced state is created, and longitudinal andcurved secondary oscillations are created by providing the piezoelectricactuator 41 with a balance section 41C1 and a contact section 41B1 in anunbalanced location instead of providing the piezoelectric actuator 41,which is an oscillator, with a contact section 41B.

[0118] In the present modification, a contact section 41B1 and a balancesection 41C1 are provided as contact sections, but the contact section41B1 alone may also be provided.

[0119]FIG. 12 is an explanatory diagram of the electrode arrangement foranother piezoelectric actuator.

[0120] The modification in FIG. 11 was configured with a full electrode404, but the piezoelectric actuator 400B of the present embodiment canbe configured with a drive electrode 405 and detection electrodes 406disposed at a location in which the contact section 41B1 and balancesection 41C1 are joined to each other, as shown in FIG. 11.

[0121] When such a configuration is employed, the longitudinaloscillation of the piezoelectric elements is vibrated by the applicationof a drive voltage to the drive electrode 405, and an imbalance iscreated in the expansion and contraction of the piezoelectric elements.Furthermore, the curved secondary oscillation is reliably vibrated bythe mechanically unbalanced state brought about by the contact section41B1 and the balance section 41C1.

[0122] The longitudinal and curved secondary oscillations are thencombined to create elliptical oscillation.

[0123] More accurate control is possible if the detection electrodes 406are used to detect the oscillation state for the same reasons as in themodification described above.

[0124] The rotor was driven in one direction in the above description,but a configuration may also be adopted such that the rotor is drivenboth forwards and backwards.

[0125]FIG. 13 is an explanatory diagram of the arrangement of electrodesin a piezoelectric actuator driven both forwards and backwards.

[0126] The electrode arrangement in the piezoelectric actuator 400C ofthe present modification is configured so as to include a middleelectrode 401 and two electrode pairs 402 and 403 disposed so as tointersect with the middle electrode 401.

[0127] With such a configuration, the middle electrode 401 and theelectrode pair 402 are driven by the application of a drive voltage inorder to achieve elliptical driving in a first direction (forward). Adrive voltage is not applied to the electrode pair 403.

[0128] As a result, the middle electrode 401 vibrates longitudinaloscillation, but an imbalance is created in the expansion andcontraction of the longitudinal oscillation of the piezoelectricelements by applying a drive voltage solely to the electrode pair 402,and curved secondary oscillation in the first direction is vibrated.

[0129] The longitudinal oscillation and the curved secondary oscillationare then combined to create elliptical oscillation of the in the firstdirection.

[0130] The middle electrode 401 and the electrode pair 403 are driven bythe application of a drive voltage in order to create an ellipticaldrive in the contact section 341B in a second direction (backwards). Adrive voltage is not applied to the electrode pair 402.

[0131] As a result, longitudinal oscillation is vibrated by the middleelectrode 401, but the expansion and contraction originating in thelongitudinal oscillation of the piezoelectric elements is renderedunbalanced by applying a drive voltage solely to the electrode pair 403out of the electrode pairs 402 and 403, and curved secondary oscillationin the second direction is vibrated.

[0132] The longitudinal oscillation and the curved secondary oscillationare then combined to create elliptical oscillation in the seconddirection.

[0133]FIG. 14 is an explanatory diagram of another arrangement ofelectrodes in a piezoelectric actuator driven both forwards andbackwards.

[0134] A middle electrode 401 and two electrode pairs 402 and 403 wereprovided in the modifications described above, but in the piezoelectricactuator 400D of the present modification, the middle electrode 401 isdispensed with and only the two electrode pairs 402 and 403 are providedas shown in FIG. 14.

[0135] With such a configuration, the electrode pair 402 is driven bythe application of a drive voltage in order to drive elliptically thecontact section 341B in the first direction (forward). A drive voltageis not applied to the electrode pair 403.

[0136] As a result, longitudinal oscillation of the piezoelectricelements is vibrated by the application of a drive voltage to theelectrode pair 402, the expansion and contraction of the piezoelectricelements are rendered unbalanced, and curved secondary oscillation inthe first direction is vibrated.

[0137] The longitudinal oscillation and the curved secondary oscillationare then combined to create elliptical oscillation in the firstdirection.

[0138] The electrode pair 403 is driven by the application of a drivevoltage in order to drive elliptically the contact section 341B in thesecond direction (backwards). A drive voltage is not applied to theelectrode pair 402.

[0139] As a result, longitudinal oscillation of the piezoelectricelements is vibrated by the application of a drive voltage to theelectrode pair 403, the expansion and contraction of the piezoelectricelements are rendered unbalanced, and curved secondary oscillation inthe second direction is vibrated.

[0140] The longitudinal oscillation and the curved secondary oscillationare then combined to create elliptical oscillation in the seconddirection.

[0141] In these cases, the electrodes to which a drive voltage is notapplied are preferably used as detection electrodes to detect theoscillation state for the same reasons as in the modifications describedabove.

[0142] The location at which the piezoelectric actuator is supported wasnot described in detail above, but it is possible to reduce oscillationloss by supporting the middle section, which is the oscillation node ofboth the longitudinal oscillation and the curved secondary oscillation.

[0143] The application of a drive device to a timing device wasdescribed above, but this approach is also applicable to a drive devicefor a mechanisms other than a time information display; for example, amechanical structure such as one that moves the arm of a mechanicaldoll. The drive device may also be used in analog display devices thatuse pointers to display temperature, air pressure, and other suchphysical quantities in addition to time information.

[0144] Effects of First Through Third Embodiments

[0145] According to the first through third embodiments as describedabove, in a timing device wherein a power generator utilizeselectromagnetic induction to convert kinetic energy into electricenergy, a piezoelectric actuator is used as a drive source for the timedisplay unit, so the time display unit is not affected by the powergenerating operation of the power generator and the time can beaccurately displayed.

[0146] [4] Fourth Embodiment

[0147] The fourth embodiment will now be described.

[0148]FIG. 15 is a partial plan view of the timing device relating tothe fourth embodiment. FIG. 16 is a cross-sectional view of one part ofthe timing device relating to the fourth embodiment. FIG. 17 is across-sectional view of another part of the timing device relating tothe fourth embodiment.

[0149] The timing device 210 is a wristwatch designed for use bywrapping a belt coupled with the main body of the device around thewrist of the user.

[0150] In general terms, the timing device 210 includes a receivingcircuit (communication means) 211, an electric power source 212, atiming unit (time display means) 213, and an operating unit 214.

[0151] The receiving circuit 211 includes a first receiving crystaloscillator 221 for creating a first standard oscillation signal, asecond receiving crystal oscillator 222 for creating a second standardoscillation signal, a receiving processor IC 223 for performingreception processing on the basis of the first standard oscillationsignal and the second standard oscillation signal, and a coil antenna224 for receiving externally transmitted electromagnetic waves.

[0152] The electric power source 212 includes a battery 231 forsupplying a source of electricity, and a battery terminal 232 forelectrically connecting the battery 231 and the base plate.

[0153] In general terms, the timing unit 213 includes a second drivingpiezoelectric actuator 241 for driving a second hand as a pointercomponent, an hour/minute driving piezoelectric actuator 242 for drivingan hour and minute hand as pointer components, a gear train section 243for transmitting the driving force for driving the pointers, a standardoscillation signal crystal oscillator 244 for keeping time, and a timingIC 245 for performing various timing processes on the basis of thestandard oscillation signals for timing.

[0154] The gear train section 243 is similar to a regular analogtimepiece and includes a second rotor 251, a second rotor pinion 252, asecond intermediate wheel 253, a second wheel 254, a second hand 255,and a second rotor pressure member 256. Furthermore, the gear trainsection 243 also includes an hour/minute rotor 261, an hour/minute rotorpinion 262, a first hour/minute intermediate wheel 263, a second hourminute intermediate wheel 264, a center wheel and pinion 265, a minutehand 266, an hour wheel 267, an hour hand 268, a minute wheel 269, and arotor pressure section 270.

[0155] The operating unit 214 includes a setting stem 271, a firstswitch 272, a second witch 273, a setting lever 274, and a yoke 275, andis designed to be able to perform various settings including timesetting and time correction, similar to common timing devices.

[0156] The relative arrangement of the coil antenna and the seconddriving piezoelectric actuator will now be described with reference toFIGS. 16 and 17.

[0157] In the fourth embodiment, assuming there is a plane perpendicularto the timing device 210, the coil antenna 224 is disposed at a locationin which the positive projection of the antenna on this plane does notoverlap the positive projection of the second driving piezoelectricactuator 241 and the hour/minute driving piezoelectric actuator 242 onthis plane, and is also disposed to form a space D1 with a specificdistance (FIG. 17) in a direction perpendicular to the thicknessdirection.

[0158] Such an arrangement makes it possible to configure a thinwristwatch wherein the thickness of the timing device 210 can bereduced.

[0159] In this case, the configuration of the second drivingpiezoelectric actuator and the hour/minute driving piezoelectricactuator is similar to those shown in FIGS. 4 through 7 and FIGS. 11through 14, so detailed descriptions are omitted.

[0160] The operation of the second driving piezoelectric actuator 241will now be described.

[0161] When an alternating-current drive signal is applied to thepiezoelectric elements 113 and 114 from the drive circuit 200 via theelectrodes 113A and 114A, oscillation that expands and contracts in thelongitudinal direction is created in the piezoelectric elements 113 and114. In this case, the piezoelectric elements 113 and 114 createlongitudinal oscillation that expands and contracts in the longitudinaldirection, as shown by the arrow in FIG. 5. When the second drivingpiezoelectric actuator 241 is electrically vibrated by the longitudinaloscillation due to the application of a drive signal to thepiezoelectric elements 113 and 114, an angular momentum is created aboutthe center of gravity of the second driving piezoelectric actuator 241by the unbalanced weight of the second driving piezoelectric actuator241. This angular momentum induces curved secondary oscillation wherebythe second driving piezoelectric actuator 241 swings in the widthdirection, as shown in FIG. 6. At this point a greater degree of curvedoscillation can be induced to create a greater angular momentum bydisposing the contact section 41B on the tip of the second drivingpiezoelectric actuator 241 opposite from the balance section 41C.

[0162] Longitudinal oscillation and curved secondary oscillation arethus created in the second driving piezoelectric actuator 241, and thelongitudinal oscillation and curved secondary oscillation are combined.The area at which the contact section 41B of the second drivingpiezoelectric actuator 241 and the second rotor 251 come in contactthereby moves along an elliptic path, as shown in FIG. 7. As a result ofthe movement of the contact section 41B along an elliptic path in thedirection of the timepiece, the force of the contact section 41B pushingon the second rotor 251 increases when the contact section 41B is in aposition expanded toward the second rotor 251. Conversely, the force ofthe contact section 41B pushing on the second rotor 251 decreases whenthe contact section 41B is expanded to a position distanced from thesecond rotor 251.

[0163] Therefore, the second rotor 251 is rotatably driven in thedirection of displacement of the contact section 41B while both types ofpressure are large, or, in other words, when the contact section 41B isin a position expanded toward the second rotor 251.

[0164] As described above, the second driving piezoelectric actuator 241rotatably drives the second rotor 251 by elliptical movement due to boththe longitudinal oscillation and the curved oscillation. At this point,the second rotor 251 is pressed against the contact section of a seconddrive actuator by a second rotor pressure member 256. The second rotor251 is therefore rotatably driven in a reliable manner.

[0165] The rotational driving of the second rotor 251 causes the secondrotor pinion 252 to rotate. The second intermediate wheel 253interlocking with the second rotor pinion 252 is then rotatably driven.

[0166] Furthermore, the second intermediate wheel 253 interlocks withthe second wheel 254, causing the second hand 255 fixed to the secondwheel 254 to move.

[0167] Also, the hour/minute driving piezoelectric actuator 242rotatably drives the hour/minute rotor 261 by elliptical movement thatresults from a combination of longitudinal and curved oscillations. Atthis point, the hour/minute rotor 261 is pressed against the contactsection of an hour/minute drive actuator by an hour/minute rotorpressure member 270. The hour/minute rotor 261 is therefore rotatablydriven in a reliable manner.

[0168] The rotational driving of the hour/minute rotor 261 causes thehour/minute rotor pinion 262 to rotate. The first hour/minuteintermediate wheel 263 interlocking with the second hour/minute rotorpinion 262 is then rotatably driven.

[0169] Furthermore, the first hour/minute intermediate wheel 263interlocks with the second hour minute intermediate wheel 264, causingthe second hour minute intermediate wheel 264 to be rotatably driven.

[0170] The second hour minute intermediate wheel 264 interlocks with thecenter wheel and pinion 265 and with the minute wheel 269 via the centerwheel and pinion 265, and induces movement in the minute hand 266 fixedto the center wheel and pinion 265 and the hour hand 268 fixed to thehour wheel 267.

[0171] The operation of the receiving circuit will now be described.

[0172] In Japan, the first receiving crystal oscillator 221 of thereceiving circuit 211 creates a first standard oscillation signalcorresponding to a 40-kHz LF standard wave, and outputs the signal tothe receiving processor IC 223. Similarly, the second receiving crystaloscillator 222 creates a second standard oscillation signalcorresponding to a 60-kHz LF standard wave, and outputs the signal tothe receiving processor IC 223.

[0173] In addition, the coil antenna 224, configured as a ferriteantenna, for example, receives an LF standard wave on which time dataare superposed.

[0174] The receiving processor IC 223 demodulates the LF standard wavereceived by the coil antenna 224 as time data, stores the time data, andtransmits the data to the timing IC.

[0175] The receiving processor IC 223 is configured to include an AGC(Automatic Gain Control) circuit, an amplification circuit, a band-passfilter, a demodulation circuit, and a decoding circuit, all not shown.

[0176] The amplification circuit of the receiving processor IC 223amplifies the LF standard wave signal received by the coil antenna 224under the gain control of the AGC circuit, and outputs the result to theband-pass filter.

[0177] The band-pass filter extracts only specific frequency componentsfrom the amplified LF standard wave signal and outputs the result to thedemodulation circuit.

[0178] The demodulation circuit smoothes the inputted specific frequencycomponents of the LF standard wave signal, demodulates the result, andoutputs it to the decoding circuit.

[0179] The decoding circuit decodes the demodulated LF standard wavesignal, and outputs the result as a reception output signal.

[0180] At this point, the AGC circuit controls the gain of theamplification circuit on the basis of the output signal of thedemodulation circuit, and performs this control so that the receptionlevel of the LF standard wave signal remains constant.

[0181] At this point, a power save mode signal, which is a signal forexerting control to reduce power consumption, is supplied from thetiming IC 245, and the receiving processor IC 223 ceases to functionwhen operation is not necessary.

[0182] Normally, the receiving processor IC 223 is controlled by thepower save mode signal so as to perform reception about once a day. Thereceiving operation is normally repeated many times when the time datacannot be received.

[0183] Electromagnetic noise is not generated in the fourth embodimentand does not affect the reception of the LF standard waves because apiezoelectric actuator is used to drive the pointers. Therefore, thereceiving operation of the receiving circuit 211 can be performed inconjunction with the pointer driving operation of the timing unit 213.

[0184] Therefore, according to the fourth embodiment, LF standard wavescan be received anytime and the time can be corrected. Furthermore,there is no need to provide a control procedure or circuit to stopdriving the pointers during the receiving operation, and the control andcircuit configuration can be simplified.

[0185] [5] Fifth Embodiment

[0186] In the fourth embodiment, assuming there is a plane perpendicularto the thickness direction of the timing device 210 (a surfaceperpendicular to the plane of paper), the coil antenna 224 is disposedat a location in which the positive projection of the antenna on thisplane does not overlap the positive projection of the second drivingpiezoelectric actuator 241 on this plane, and is also disposed to form aspace with a specific distance in a direction perpendicular to thethickness direction.

[0187] Accordingly, in the fifth embodiment, the coil antenna isdisposed at a location in which at least part of the positive projectionof the antenna on a plane perpendicular to the thickness direction ofthe timing device overlaps the positive projection of either the seconddriving piezoelectric actuator or the hour/minute driving piezoelectricactuator on the plane, and is also disposed to form a space with aspecific distance in the thickness direction.

[0188]FIG. 18 shows a cross-sectional view of part of the timing deviceof the fifth embodiment. The components in FIG. 18 similar to those inFIG. 16 or 17 are denoted by the same symbols.

[0189] Assuming there is a plane perpendicular to the thicknessdirection, the coil antenna 224 is disposed at a location in which atleast part of the positive projection of the coil antenna 224 on thisplane overlaps the positive projection of the second drivingpiezoelectric actuator 241 on this plane, and is also disposed to form aspace with a specific distance D2 in the thickness direction.

[0190] It is possible to reduce the size of the timing device with sucha configuration.

[0191] Furthermore, LF standard waves can be received anytime to correctthe time, similar to the fourth embodiment. Moreover, there is no needfor a control procedure or circuit to stop driving the pointers duringthe receiving operation, and the control and circuit configuration canbe simplified.

[0192] Modification of the Fourth and Fifth Embodiments

[0193] The case of using a receiving device for receiving LF standardwaves as a communication unit was described above, but it is alsopossible to use a wireless communication device for both reception andtransmission.

[0194] Also, the case of including a second driving piezoelectricactuator and a hour/minute driving piezoelectric actuator was describedin all the embodiments described above, but it is also possible to use aconfiguration wherein three piezoelectric actuators are provided forseparately driving the second hand, the minute hand, and the hour hand,or one piezoelectric actuator is provided for driving the second hand,the minute hand, and the hour hands.

[0195] Also, a ferrite antenna is used as an antenna for receiving LFstandard waves on which time information is superposed in theembodiments described above, but either a loop antenna or a ferriteantenna may be used when FM multiplex broadcasting (76 MHz to 108 MHz)on which time information is superposed is received, and either amicrostrip antenna or a helical antenna may be used when electromagneticwaves (1.5 GHz) on which time information is superposed are receivedfrom a GPS satellite.

[0196] Also, in the fourth and fifth embodiments described above, thetime information for the hours, minutes, and second is automaticallycorrected based on LF standard waves on which time information issuperposed, but this process is not limited to the time display forhours, minutes, and second, and may include the automatic correction ofa date display. Since date information is included in the LF standardwaves as described above, the date display can be automaticallycorrected based on the LF standard waves when a piezoelectric actuatorfor driving a calendar display is included in addition to thepiezoelectric actuator for driving the hour/minute/second display. Inthis case, an element for detecting the calendar display position may beadded.

[0197] Also, a configuration wherein LF standard waves were received aselectromagnetic waves on which time information is superposed was usedin the fourth and fifth embodiments described above, but it is alsopossible to use a configuration wherein a GPS signal, a pager signal ina FLEX-TD format, an FM multiplex signal, a CDMA signal, or other suchvarious signals are used instead of LF standard waves.

[0198] According to the fourth and fifth embodiments described above,the communication process performed by the communication unit with theexternal communication device via the antenna is not affected, and canbe performed in conjunction with the time display operation and thecommunication operation, because a piezoelectric actuator is used as thedrive source for the time display unit.

[0199] Thus, there is no need for a control procedure or circuit to stopthe time display operation during the communication operation, and thecontrol and the circuit configuration can be simplified.

[0200] The terms “front,” “back, “up,” “down,” “perpendicular,”“horizontal,” “slanted,” and other direction-related terms used aboveindicate the directions in the diagrams used herein. Therefore, thedirection-related terms used to describe the present invention should beinterpreted in relative terms as applied to the diagrams used herein.

[0201] “Substantially,” “essentially,” “about,” and other terms usedabove that represent an approximation indicate a reasonable amount ofdeviation that does not bring about a considerable change as a result.Terms that represent these approximations should be interpreted so as toinclude an error of about ±5% at least, as long as there is noconsiderable change due to the deviation.

[0202] This specification claims priority to Japanese Patent ApplicationNos. 2003-044341 and 2003-094255. All the disclosures in Japanese PatentApplication Nos. 2003-044341 and 2003-094255 are incorporated herein byreference.

[0203] The embodiments described above constitute one part of theembodiments of the present invention, and it is apparent to thoseskilled in the art that it is possible to add modifications to theabove-described embodiments by using the above-described disclosurewithout exceeding the range of the present invention as defined in theclaims. The above-described embodiments furthermore do not limit therange of the present invention, which is defined by the accompanyingclaims or equivalents thereof, and are only designed to provide adescription of the present invention.

What is claimed is:
 1. A drive device, comprising: a generator unitprovided with a generating coil and designed to convert kinetic energyinto electric energy by utilizing electromagnetic induction; a storageunit to store the electric energy; and a drive unit having apiezoelectric actuator to which the electric energy from the storageunit is supplied, and a mechanical structure driven by the piezoelectricactuator.
 2. The drive device according to claim 1, wherein thegenerator unit is disposed at a location in which the positiveprojection of the generator on a plane perpendicular to the thicknessdirection of the drive device does not overlap the positive projectionof the piezoelectric actuator on this plane.
 3. The drive deviceaccording to claim 1, wherein the generator unit is disposed at alocation in which at least part of the positive projection of thegenerator on a plane perpendicular to the thickness direction of thedrive device overlaps the positive projection of the piezoelectricactuator on this plane.
 4. The drive device according to claim 1 furtherhaving a structural member, wherein the generator unit is disposed onone side of the structural member, and the piezoelectric actuator isdisposed on the other side of the structural member.
 5. The drive deviceaccording to claim 1, wherein: the piezoelectric actuator comprises anoscillating plate having a plate-shaped piezoelectric element and areinforcing plate stacked on the piezoelectric element, a contactsection provided to the longitudinal tip of the oscillating plate, and aholding section for holding the oscillating plate; and the contactsection is disposed at a location in which the mechanical structure isdriven by displacement that accompanies the oscillation of thepiezoelectric element.
 6. The drive device according to claim 1, whereinthe mechanical structure has a time display unit for displaying timeinformation.
 7. The drive device according to claim 6, wherein: themechanical structure further has a rotor; and the piezoelectric actuatoris configured so as to rotatably drive the rotor by elliptical movementresulting from a combination of longitudinal oscillation and curvedoscillation.
 8. The drive device according to claim 7, wherein the timedisplay unit comprises pointers for displaying the time information anda pointer driving actuator for driving the pointers.
 9. The drive deviceaccording to claim 1, wherein the mechanical structure includes ananalog display device having analog pointers for displaying physicalquantities.
 10. A timing device, comprising: an antenna; a communicationunit to communicate with an external communication device via theantenna; and a drive unit having a piezoelectric actuator thatoscillates according to a signal from the communication unit, and amechanical structure designed to be driven by the piezoelectric actuatorand provided with a time display unit for displaying time information.11. The timing device according to claim 10, wherein: the communicationunit comprises a receiving unit for receiving time information at aspecific cycle from the outside via the antenna, and a current timecounter unit for sequentially updating the current time informationusing the time corresponding to the time information received by thereceiving unit as a reference; and the mechanical structure displays thetime information on the time display unit on the basis of the currenttime information from the current time counter unit.
 12. The timingdevice according to claim 10, wherein: the mechanical structure furtherhas a rotor; and the piezoelectric actuator is configured so as torotatably drive the rotor by elliptical movement resulting from acombination of longitudinal oscillation and curved oscillation.
 13. Thetiming device according to claim 10, wherein: the piezoelectric actuatorcomprises an oscillating plate having a plate-shaped piezoelectricelement and a reinforcing plate stacked on the piezoelectric element, acontact section provided to the longitudinal tip of the oscillatingplate, a support member, and a holding section for holding theoscillating plate on the support member; and the contact section isdisposed at a location in which a rotor of the mechanical structure isdriven by displacement resulting from the oscillation of thepiezoelectric element.
 14. The timing device according to claim 10,wherein: the time display unit comprises pointers for displaying timeinformation and a pointer driving actuator for driving the pointers; andthe antenna is disposed at a location in which the positive projectionof the antenna on a plane perpendicular to the thickness direction ofthe timing device does not overlap the positive projection of thepointer driving piezoelectric actuator on the plane, and is alsodisposed to be separated by a specific distance in a directionperpendicular to the thickness direction.
 15. The timing deviceaccording to claim 10, wherein: the time display unit comprises pointersfor displaying the time information and a pointer driving actuator fordriving the pointers; and the antenna is disposed at a location in whichat least part of the positive projection of the antenna on a planeperpendicular to the thickness direction of the timing device overlapsthe positive projection of the pointer driving piezoelectric actuator onthe plane, and is also disposed to be separated by a specific distancein a direction perpendicular to the thickness direction.
 16. A drivedevice, comprising: generating means for converting kinetic energy intoelectric energy by utilizing electromagnetic induction; storage meansfor storing the electric energy; and drive means having a piezoelectricactuator to which the electric energy from the storage means issupplied, and a mechanical structure driven by the piezoelectricactuator.
 17. The drive device according to claim 16, wherein the drivemeans further comprises time display means driven by the piezoelectricactuator and designed for displaying the time.
 18. A timing device,comprising: communication means for communicating with an externalcommunication device; and time display means provided with apiezoelectric actuator that vibrates according to signals from thecommunication means, and designed for displaying the time.
 19. A methodfor controlling a timing device, comprising: a preparation step forpreparing a timing device comprising an antenna, a control unit, apiezoelectric actuator, and a mechanical structure having a time displayunit; a time display step wherein the control unit drives thepiezoelectric actuator, the piezoelectric actuator operates themechanical structure, and the time is displayed on the time displayunit; and a communication step wherein the control unit communicateswith an external communication device via an antenna in conjunction withthe time display step.
 20. The method for controlling a timing deviceaccording to claim 19, wherein: the communication step comprises areceiving step wherein time information is received from the outside viathe antenna at a specific cycle, and a current time counting stepwherein current time information is sequentially updated using the timecorresponding to the time information as a standard; and the timedisplay step involves displaying the time on the time display unit onthe basis of the current time information obtained in the current timecounting step.
 21. A method for controlling a timing device, comprising:a preparation step to prepare a timing device comprising a control unit,a piezoelectric actuator, and a mechanical structure having a timedisplay unit; a current time counting step to update sequentiallycurrent time information by the control unit using the time informationas a standard; and a time display step to display the time informationon the time display unit by the control unit driving the mechanicalstructure by the piezoelectric actuator on the basis of the current timeinformation.